A multi-disciplinary group of NIH-funded investigators at the University of California, Davis (UCD), has assembled an NIH Shared Instrumentation Grant application requesting a state-of-the-art cell sorter. This group includes individuals from the Schools of Medicine and Veterinary Medicine, and the California Regional Primate Research Center. The request for a cell sorter (MoFlo Multi-Laser Flow Cytometer, Cytomation) is based on the needs of many of these investigators for obtaining sufficient numbers of purified cell populations, largely from in vivo (i.e., animal) settings. The instrument will significantly enhance and expand numerous ongoing research projects by making it possible to conduct detailed molecular and immunological analysis on specific cell types that can not be efficiently obtained by other methods. Importantly, the recruitment of new faculty members to the Schools of Medicine and Veterinary Medicine will benefit greatly if a versatile cell sorter is available; this includes about 20 new faculty in both schools as the endowed Rowe Program in Medical Genetics and the Center for Comparative Medicine. Many of these new facility also require the capabilities of the MoFlo Cell sorter to elucidate mechanisms for genetic and infectious disease in a variety of animal models. The plan is to incorporate the MoFlo Cell Sorter into the current Flow Cytometry Laboratory in the Department of Medical Pathology which has a well-established management system that currently provides technical service and consultation for flow cytometry to over 40 users in many research units on the Davis Campus and at the UCD Medical Center in Sacramento. With the addition of the cell sorter and institutional commitment, the Flow Cytometry/Cell Sorter Laboratory will evolve into an Optical Biology Laboratory which will continue to serve and enhance many diverse research efforts at UCD.